// Copyright (c) 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_RENDERER_PEPPER_PEPPER_VIDEO_DECODER_HOST_H_
#define CONTENT_RENDERER_PEPPER_PEPPER_VIDEO_DECODER_HOST_H_

#include <stdint.h>

#include <list>
#include <map>
#include <memory>
#include <set>
#include <vector>

#include "base/containers/hash_tables.h"
#include "base/macros.h"
#include "base/memory/scoped_vector.h"
#include "content/common/content_export.h"
#include "media/video/video_decode_accelerator.h"
#include "ppapi/c/pp_codecs.h"
#include "ppapi/host/host_message_context.h"
#include "ppapi/host/resource_host.h"
#include "ppapi/proxy/resource_message_params.h"

namespace base {
class SharedMemory;
}

namespace content {

class RendererPpapiHost;
class VideoDecoderShim;

class CONTENT_EXPORT PepperVideoDecoderHost
    : public ppapi::host::ResourceHost,
      public media::VideoDecodeAccelerator::Client {
public:
    PepperVideoDecoderHost(RendererPpapiHost* host,
        PP_Instance instance,
        PP_Resource resource);
    ~PepperVideoDecoderHost() override;

private:
    enum class PictureBufferState {
        ASSIGNED,
        IN_USE,
        DISMISSED,
    };

    struct PendingDecode {
        PendingDecode(int32_t decode_id,
            uint32_t shm_id,
            uint32_t size,
            const ppapi::host::ReplyMessageContext& reply_context);
        ~PendingDecode();

        const int32_t decode_id;
        const uint32_t shm_id;
        const uint32_t size;
        const ppapi::host::ReplyMessageContext reply_context;
    };
    typedef std::list<PendingDecode> PendingDecodeList;

    friend class VideoDecoderShim;

    // ResourceHost implementation.
    int32_t OnResourceMessageReceived(
        const IPC::Message& msg,
        ppapi::host::HostMessageContext* context) override;

    // media::VideoDecodeAccelerator::Client implementation.
    void ProvidePictureBuffers(uint32_t requested_num_of_buffers,
        media::VideoPixelFormat format,
        uint32_t textures_per_buffer,
        const gfx::Size& dimensions,
        uint32_t texture_target) override;
    void DismissPictureBuffer(int32_t picture_buffer_id) override;
    void PictureReady(const media::Picture& picture) override;
    void NotifyEndOfBitstreamBuffer(int32_t bitstream_buffer_id) override;
    void NotifyFlushDone() override;
    void NotifyResetDone() override;
    void NotifyError(media::VideoDecodeAccelerator::Error error) override;

    int32_t OnHostMsgInitialize(ppapi::host::HostMessageContext* context,
        const ppapi::HostResource& graphics_context,
        PP_VideoProfile profile,
        PP_HardwareAcceleration acceleration,
        uint32_t min_picture_count);
    int32_t OnHostMsgGetShm(ppapi::host::HostMessageContext* context,
        uint32_t shm_id,
        uint32_t shm_size);
    int32_t OnHostMsgDecode(ppapi::host::HostMessageContext* context,
        uint32_t shm_id,
        uint32_t size,
        int32_t decode_id);
    int32_t OnHostMsgAssignTextures(ppapi::host::HostMessageContext* context,
        const PP_Size& size,
        const std::vector<uint32_t>& texture_ids);
    int32_t OnHostMsgRecyclePicture(ppapi::host::HostMessageContext* context,
        uint32_t picture_id);
    int32_t OnHostMsgFlush(ppapi::host::HostMessageContext* context);
    int32_t OnHostMsgReset(ppapi::host::HostMessageContext* context);

    // These methods are needed by VideoDecodeShim, to look like a
    // VideoDecodeAccelerator.
    const uint8_t* DecodeIdToAddress(uint32_t decode_id);
    void RequestTextures(uint32_t requested_num_of_buffers,
        const gfx::Size& dimensions,
        uint32_t texture_target,
        const std::vector<gpu::Mailbox>& mailboxes);

    // Tries to initialize software decoder. Returns true on success.
    bool TryFallbackToSoftwareDecoder();

    PendingDecodeList::iterator GetPendingDecodeById(int32_t decode_id);

    // Non-owning pointer.
    RendererPpapiHost* renderer_ppapi_host_;

    media::VideoCodecProfile profile_;

    std::unique_ptr<media::VideoDecodeAccelerator> decoder_;

    bool software_fallback_allowed_ = false;
    bool software_fallback_used_ = false;

    int pending_texture_requests_ = 0;

    // Set after software decoder fallback to dismiss all outstanding texture
    // requests.
    int assign_textures_messages_to_dismiss_ = 0;

    // A vector holding our shm buffers, in sync with a similar vector in the
    // resource. We use a buffer's index in these vectors as its id on both sides
    // of the proxy. Only add buffers or update them in place so as not to
    // invalidate these ids.
    ScopedVector<base::SharedMemory> shm_buffers_;
    // A vector of true/false indicating if a shm buffer is in use by the decoder.
    // This is parallel to |shm_buffers_|.
    std::vector<uint8_t> shm_buffer_busy_;

    uint32_t min_picture_count_;
    typedef std::map<uint32_t, PictureBufferState> PictureBufferMap;
    PictureBufferMap picture_buffer_map_;

    // Keeps list of pending decodes.
    PendingDecodeList pending_decodes_;

    ppapi::host::ReplyMessageContext flush_reply_context_;
    ppapi::host::ReplyMessageContext reset_reply_context_;

    bool initialized_ = false;

    DISALLOW_COPY_AND_ASSIGN(PepperVideoDecoderHost);
};

} // namespace content

#endif // CONTENT_RENDERER_PEPPER_PEPPER_VIDEO_DECODER_HOST_H_
